Semantic highlighting spike

Very simple approach: For each identifier, set the hash of the range
where it's defined as its 'id' and use it in the VSCode extension to
generate unique colors.

Thus, the generated colors are per-file. They are also quite fragile,
and I'm not entirely sure why. Looks like we need to make sure the
same ranges aren't overwritten by a later request?

2 files changed, 6 insertions, 1 deletions

diff --git a/crates/ra_lsp_server/src/main_loop/handlers.rs b/crates/ra_lsp_server/src/main_loop/handlers.rs
index a82ae696b..5dfd64ed4 100644
--- a/crates/ra_lsp_server/src/main_loop/handlers.rs
+++ b/crates/ra_lsp_server/src/main_loop/handlers.rs
@@ -872,7 +872,11 @@ fn highlight(world: &ServerWorld, file_id: FileId) -> Result<Vec<Decoration>> {
         .analysis()
         .highlight(file_id)?
         .into_iter()
-        .map(|h| Decoration { range: h.range.conv_with(&line_index), tag: h.tag })
+        .map(|h| Decoration {
+            range: h.range.conv_with(&line_index),
+            tag: h.tag,
+            id: h.id.map(|x| x.to_string()),
+        })
         .collect();
     Ok(res)
 }
diff --git a/crates/ra_lsp_server/src/req.rs b/crates/ra_lsp_server/src/req.rs
index 6090eb7b9..cea0e6ce7 100644
--- a/crates/ra_lsp_server/src/req.rs
+++ b/crates/ra_lsp_server/src/req.rs
@@ -129,6 +129,7 @@ pub struct PublishDecorationsParams {
 pub struct Decoration {
     pub range: Range,
     pub tag: &'static str,
+    pub id: Option<String>,
 }
 
 pub enum ParentModule {}